1. Field of the Invention
This invention relates to an apparatus for automatically preparing measurement programs used in operating measurement apparatus for measuring the properties of electronic circuits such as semiconductor integrated circuits (hereinafter referred to as ICs).
2. Description of the Related Art
Generally, the properties of electronic circuits, of which semiconductor integrated circuits are representative, are measured and tested after the circuits are designed and produced, and a measurement apparatus called a general IC test system is used for this purpose. This type of measurement apparatus is generally equipped with a plurality of signal generating means and measuring means, etc. Various measurements and tests can be conducted by operating such means in accordance with relevant measurement programs.
FIG. 4 is a block diagram illustrating the entire configuration of a system for measuring the properties of electronic circuits which utilizes such a measurement apparatus. A measurement apparatus 1 is connected, through the intermediary of a connection cable 2, to a measurement circuit 3. The measurement circuit 3 includes an interface circuit 4 connected to the connection cable 2, a peripheral circuit 5, and a socket jig 6. Connected to the socket jig 6 is an IC 7, which is the object to be tested. Here, the peripheral circuit 5 serves to create the peripheral condition in which the IC is to be actually used and includes a multitude of change-over switches (relays) to enable the IC 7 to be tested.
The measurement apparatus 1 operates in accordance with a measurement program, and an electric signal is input to the IC 7 through the interface 4, the peripheral circuit 5, etc. This causes the IC 7 to operate and the output thereof is transmitted to the measurement apparatus 1 through the peripheral circuit 5 and the interface circuit 4. In this way, various tests are performed on the IC 7 in accordance with the particular measurement program.
Here, the measurement program for operating the measurement apparatus 1, the peripheral circuit 5, and the interface circuit 4 are inherent to the circuit design of the IC 7 to be tested. Conventionally, such a measurement program is prepared by the following procedure:
Step 1: the measurement specifications for the IC 7 are prepared by selecting the items for measurement in accordance with the device specifications prepared when the IC 7 is designed.
Step 2: concrete measurement methods according to the measurement apparatus 1 are examined.
Step 3: the requisite peripheral circuit 5 and the interface 4 for conducting the measurement are designed.
Step 4: the peripheral circuit 5 and the interface circuit 4 are produced and connected to each other. At the same time, the socket jig 6 is connected to the peripheral circuit 5, thereby completing the measurement circuit 3.
Step 5: a measurement program using an exclusive language form for the measurement apparatus 1 is prepared in accordance with the items for measurement and the measurement method of Steps 1 and 2, respectively.
Step 6: the measurement circuit 3 is connected to the measurement apparatus 1 through the connection cable 2. At the same time, the IC 7 is connected to the socket jig 6. Then, the measurement apparatus 1 is operated in accordance with the measurement program in order to conduct operational verification (generally referred to as debug) to see whether the desired measurement can be conducted.
Step 7: the relation between the measurement data obtained in Step 6 and the device specifications of the IC 7 is checked.
Step 8: the order of measurement is examined again for the purpose, for example, of shortening the measurement time or improving the quality of the data.
Step 9: the final specifications of the measurement program and the measurement circuit 3 are prepared.
If the desired measurement data cannot be obtained in Step 7, it is necessary to repeat Steps 2 through 7 to prepare the measurement program and the measurement circuit again. If the desired measurement still cannot be obtained, the measurement specifications of the IC 7 may be changed.
Measurement programs have been prepared that follow such steps as those described above. Traditionally, Step 1 was performed by a designer of the IC 7 and Steps 2 through 9 by a specialist testing engineer.
Steps 2 through 9 had to be performed by a testing engineer having a thorough knowledge of the hardware and software of each model of the existing measurement apparatus 1 using different tester languages according to the language forms inherent to them.
As described above, the preparation of the measurement programs has been entirely dependent on human labor, requiring a great amount of effort and time. Further, because of this dependence on human effort, it has been subject to human error and the quality of measurement programs has been greatly influenced by the depth of knowledge and experience of the testing engineer.